Overview:This 14-minute film describes the connection between the infectious parasitic disease malaria and the genetic disease sickle cell anemia - one of the best-understood examples of natural selection in humans.

Author/Source:Howard Hughes Medical Institute

Grade level:13-16

Time:15-30 minutes

Teaching tips:HHMI provides a variety of teacher resources for use with this video: an in-depth film guide, student quiz, two worksheets and three student lessons.

Inherited characteristics affect the likelihood of an organism's survival and reproduction.

Over time, the proportion of individuals with advantageous characteristics may increase (and the proportion with disadvantageous characteristics may decrease) due to their likelihood of surviving and reproducing.

Traits that confer an advantage may persist in the population and are called adaptations.

Depending on environmental conditions, inherited characteristics may be advantageous, neutral, or detrimental.

Natural selection can act on the variation in a population in different ways.

Natural selection sometimes favors heterozygotes over homozygotes at a locus.

Heterozygote advantage preserves genetic variation at that locus (i.e., within the population, it maintains multiple alleles at that locus).